Tokyo, Japan – In diligent, exhausted Japan, self-described elite "competitive sleepers" vied to lie down, relax and nap the fastest and deepest in a contest organised by a mattress company.

The Tokyo competition, dubbed "Matt Race," saw dozens of participants fitted with sleep-tracking devices sprawl on comfy mattresses to slumber for up to 90 minutes on Monday, competing for the top prize of over two million yen ($14,000).

"Japan is often described as a country suffering from sleep deprivation, and people here are very diligent," Riichiro Nakama, creative director at organiser Koala Sleep Japan, the mattress company.

Inside a dimly lit room, participants slept with monitors attached to their heads, some cradling stuffed toys.

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"By turning it into an event like this, I think we can get people to sleep together, raise interest in sleep," Nakama said.

OECD data showed in 2021 that Japanese people slept an average of seven hours 24 minutes a day – the least of all OECD nations within the group. Experts cite long working and commuting hours and a busy nightlife economy as contributing factors.

"It was over in an instant. I almost wish I could have slept a little longer," participant Chisato Honda, 32, told AFP. "It was a happy competition," he added.

The winner was chosen based on how quickly and soundly they slept.

"I want to live on my own, so I think I'll use the money for the moving costs," said Suimii, the contest winner who only gave her nickname. "I also want a bed like a princess's, so I think I'll buy that bed."